The disclosure relates to shaped glass laminates and methods for forming such laminates, and more particularly to shaped glass laminates including glass substrates that differ from one another and exhibit with minimal shape mismatch between one another.
A typical glass laminate is shown in FIG. 1 and includes a first curved glass substrate 110, a second curved glass substrate 120, and an intervening interlayer 130 disposed between the first curved glass substrate and the second curved glass substrate. Such laminates are typically formed by shaping or curving a first glass substrate and a second glass substrate simultaneously to provide a first curved glass substrate and a second glass substrate having a substantially similar or identical shape to one another. Various methods are used to shape the glass substrates including co-shaping which shape both glass substrates simultaneously by stacking by the glass substrates on top of one another to form a stack and co-shaping the stack. Methods of co-shaping include co-sagging which uses gravity to sag or shape a pair or stack of the first and second glass substrates simultaneously while heating the stack until the stack reaches a viscoelastic phase. Other methods include co-shaping using molds or a vacuum alone or in combination with one another or in combination with co-sagging.
One co-shaping example is illustrated in FIG. 2, which shows a bending frame 200 that has a first radius of curvature R1, and a second radius of curvature R2 to form a complexly curved glass substrate by co-sagging. To co-sag two glass substrates, such glass substrates are stacked on top of one another with intervening separation powder, which may include calcium carbonate. The stack is placed on the bending frame and the stack and bending frame are heated in a furnace until the glass substrates achieve a temperature equal to their softening temperature. At such a temperature, the glass substrates are bent or sagged by gravity. In some embodiments, a vacuum and/or mold can be used to facilitate co-sagging.
In such known laminates, the glass substrates have a thickness in a range from about 1.6 mm to about 3 mm. In some known laminates, the first glass substrate and the second glass substrate have respective compositions that are substantially identical or substantially similar to one another and thus properties similar to one another.
There is a need for laminates that are lightweight and thus thinner to reduce the weight of vehicles that incorporate such laminates. Accordingly, there is a need for laminates with thinner glass substrates and potentially laminates with two compositionally different glass substrates.